Process oe making hollow drill-rods and the like



P.A.E.ARMSTRONG. PROCESS OF MAKING HOLLOW DRILL 3 AND THE LIKE. APPLICATION FILED JAN. 919.

Patented N 0v. 11, 1919.

INVENTOR ATTORNEY PERCY A. E. ARMSTRONG, 0F DOUDONVILLE, NEW YORK.

PROCESS OF MAKING HOLLOW DRILL-RODS AND THE LIKE.

Specification of Letters Patent.

Patented. Nov. 11, 1919.

Application filed January 17, 1919. Serial No. 271,609.

To all whom it may concern:

Be it known that I, PERCY A. E. ARM-V srRoNo, a subject of the King of Great Britain, and a resident of Loudonville,

- county of Albany, and State of New York, have invented certain new and useful Imto which the invention relates a billet of steel is provided having a longitudinal, preferably axial, opening or bore therein. Into this opening there is placed a core, which, in the case of making drill rod, is preferably of iron or steel somewhat milder and more ductile than the drill rod steel. This core is reduced in cross section and increased in length along with the billet, as the latter is rolled or otherwise worked for elongation and reduction of cross section. Heretofore, so far as I am aware, such cores have been all in one piece and have been withdrawn from one end of the drill rod after rolling.

A core in accordance with my present invention is in two parts which may be of un-' equal length, but preferably the core is parted at aboutthe middle and the two parts are about the same length. The core parts are prevented from welding together at their meeting ends by the presence of weld-preventing material.

The bore of the billet, or the outside of the core, or both, may be coated or treated, or material may be interposed between the billet and core in any desired way, to prevent weldifig during the rolling or other working of the metal for elongation and reduction of cross section and to facilitate core removal. I prefer to make use of a coatin of talc or a coating of aluminum oXid o tained as byplating With aluminum and subsequently oxidizing the aluminum, but other modes of preventing welding may be employed. The use of aluminum oxid for this purpose is described and claimed 1n my copending application No. 271,610, filed on even date herewith.

When the rolling or other working of the metal is completed, the elongated core parts are each withdrawn from the opposite ends of the completed drill rod or other tubular body, leaving an opening or bore extending posed ends to through the length thereof. If, by any chance, any of the material from the billet should get in between the core parts it can be easily removed as by knocking it out with a rod.

The accompanying drawing will serve to give an understanding of one way in which my invention may be carried out. Figure 1 of said drawing is a longitudinal cross sectional view, with parts broken away, of a longitudinally apertured billet with the core parts in place therein prior to rolling or other working operations for elongation and reduction of cross section, and Fig. 2 is a similar View, on an enlarged scale, of the tubular article, as a drill rod or the like, after rolling and prior to withdrawal of the core parts.

I The billet 10 has the longitudinal bore 11 formed in any desired manner. In putting the core parts 12 and 13 in place therein the billet may be heated, if desired, or it may be cold and the core parts may be located against movement therein in any desired manner, as by Welding to the ends of the billet. The two core portions 12 and 13 are shown provided with a coating 14 of weldpreventing material, which may be of any desired character and thickness, and instead of being applied to the cores it may be applied to the core and ends of the billet, or to both billet and core, or may be merely interposed between the core and the walls of the bore, or may be applied in other ways. The material or coating supplied to prevent the ends of the core member from welding together is indicated at 15, 16.

When the core members extend beyond the ends of the billet, which they preferably do, as shown at 17, 18, though this is not essential, the coating of weld-preventing material is preferably applied upon the eX- prevent welding at or near the ends when the parts take on formation after rolling or other working, such as shown in Fig. 2.

The present invention is not dependent upon the use of any particular material or mode of preventing welding within the billet bore, so long as the core is in separate parts and is adapted to be withdrawn part from one end and part from the other.

The projectingends of the core portions are not reduced-in cross section by working in the same proportion as cross sectional reduction takes place in the thicker material of the billet intermediate the ends, and may be used to advantage for attaching core pulling means. In this way substantial core heads 19, 20 may' be formed, on which devices forpulling out the cores may be securely clamped or otherwise fastened.

In case the core parts, or either of them, do not extend beyond the ends of the billet, or in case they do so extend and have been located against movement, as by a preliminary welding' to the ends of the billet, the rolled tubular member may be broken or cut off at its ends around the core, leaving the core ends projecting for fastening to in pulling out the core, but Where the core ends project beyond the ends of the billet, as shown, no cutting or breaking off or other intermediate treatment is required between the working operation, as rolling or the like, and the pulling of the core members from the drill rod or other tubular body produced.

Among other advantagesobtained by the invention, it is to be observed that there is a distinct gain in the time required for removal, as, for example, by pulling from both ends at the same time the core can be pulled out in about half the time required when the entire core is pulled from one end. F urthermore, with a long core pulled entirely from one end there may be a considerable development of heat in localized areas due to friction, molecular adhesion and the like causes, which may result in seizing or firing up or welding taking place between the core and the drill rod steel, for example, in such localized areas. Such possibility is greatly reduced by the present invention, as the average distance which any part of the core must travel within the bore before it emerges therefrom is only onehalf as great as with the one-piece core of the same total length,

While the invention is especially well adapted for making hollow drill rod of steel, it is applicable to the production of tubular bodies of Various kinds and from various materials.

I claim:

1. The process of making tubular bodies which comprises introducing a two-part core into a longitudinally'apertured billet, elongating and reducing the cross section of the billet and core as by rolling, while pre- Venting welding of the parts together by application of a weld-preventing agent, and withdrawing the core portions from each end of the tubular body produced.

2. The process of making tubular bodies which comprises applying weld-preventing material to a two-part core, introducing such two-part core into a longitudinally apertured billet, elongating and reducing the cross section of the billet and core as by rolling, and withdrawing both core portions substantially simultaneously from the opposite ends of the tubular body produced.

In testimony that I claim the foregoing, I have hereto set my hand, this 14th day of January, 1919.

PERCY A. E. ARMSTRONG. 

